This invention relates to the useful recovery of heat. In particular, it relates to devices and techniques effective to return radiant energy emitted from an opening either back to that opening (e.g., the open door of an industrial furnace), or directly to material being processed at high temperature.
The problem of preventing heat loss (i.e., conserving energy) in a wide variety of industrial situations has been common for many years and has recently become increasingly important as the world's energy supplies dwindle and the cost of generating heat increases. Although more, and better, insulation surrounding a unit to be maintained at an elevated temperature (e.g., an industrial furnace) may be valuable, it is not a complete answer, since, in many circumstances, there must be continuous access to the heated region (e.g., an open door to the furnace). Such openings are common, for example, where items to be treated in a heated environment are processed on a continuous, rather than a batch, basis.
While convection currents through such an opening can be inhibited in various ways, heretofore there has been no way to prevent the radiation of substantial amounts of infrared energy through the opening. Although the energy losses resulting from such radiation have been substantial, they have remained as an unsolved problem because there have been no suitable devices or techniques to deal with them.
In view of the foregoing discussion, it is a principle object of the present invention to provide devices and techniques for recuperating heat in the form of radiant energy. It is a further object to provide such devices which are relatively inexpensive to manufacture and relatively easy to install and maintain.